There are two schools of thought when it comes to cleaning heavy snow off shrubs, and both have their own merits. One school feels you should leave things alone until weather improves, since there is a high likelihood of breaking extra branches with your attempts. Worst of all, would be cutting off some bent branches that will eventually spring back when weather improves.
The other school of thought is the sooner you get heavy snow off shrubs the better.
First, some trees and shrubs in the Arborvitae family don’t fair well in heavy snow storms anytime. As soon as snow starts to build-up on these fragile evergreens, branches begin bending. Once they are slightly bent, they become susceptible to even more snow build-up and breakage.
Second, would be if you have some neatly pruned pom-pom evergreens in your yard. It is far too easy for ‘sticky’ snow to build-up on these expensive specimens and either lay them open or bend them over. Neither situation has a good outcome.
Third would be the trees and shrubs with softwood. You know the ones; they break first in every storm. Ornamental Pears come to mind first, but are usually too tall to effectively knock the snow off.
With either method, being pro-active or re-active to removing snow from plants, they often have excessive build-up before you are able to act. If they are bent to the ground and frozen, it is probably best to leave them. However, if it is just a few big blobs of snow holding them down, strategically removing that snow will allow many branches and trees to begin straightening. Do not use a shovel to remove the snow or hit a branch hoping to knock the snow loose. Use a broom to gently brush accumulated snow away from the branches of evergreen or deciduous plants.
Once spring arrives it may be necessary to stake and/or wrap some of the plants that received the most damage. The best material for bundling multi-stemmed plants back together is that green stretchy tape sold at most garden centers. Otherwise a decent strength twine will do, just be sure to check your plants periodically to see if the twine may need loosened.
I found this article while perusing garden blogs online. It's from Bob's Blog maintained by Robert Donnan Landscape. It seemed very appropriate for our first major snowstorm of the season. Check them out online at donnan.com
Article and photos from donnan.com